Ian, help is on the way, the ECMAScript 4th edition draft specification contains a new keyword, "let", that can be used in place of "var" to provide block-level scoping. Details for the curious:
http://wiki.ecmascript.org/doku.php?id=proposals:block_expressions Francis Cheng | Senior Technical Writer | Adobe Systems, Inc. http://blogs.adobe.com/fcheng -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ian Thomas Sent: Thursday, March 27, 2008 1:23 PM To: Flash Coders List Subject: Re: [Flashcoders] Variable scope within for loops: reusingiteratorvariables AFAIK, in AS2 the Flash IDE didn't respect block level scoping, but MTASC did, which led to some confusion. That leads some people to think that AS2 as a language has block level scoping. AS3 definitely doesn't respect block scopes, and I curse every time I trip over that 'variable declared twice' issue. I wish it did. Ian On Thu, Mar 27, 2008 at 8:09 PM, Juan Pablo Califano <[EMAIL PROTECTED]> wrote: > for (var i:int = 0; i < 10; i++) > > { > if (i == 5) break; > } > trace(i); > > Mmm, have you actually tested the example? Because it does trace 5, since, > as it was explained earlier in this thread, there is no block level scoping > in AS 3.0. In fact, and this was mentioned too, all var declarations are > "moved up" to be executed as the first actions run in a function's code (I > believe that was called hoisting, but I might be wrong). > > Cheers > Juan Pablo Califano > > 2008/3/27, Steven Sacks <[EMAIL PROTECTED]>: > > > > > > function doSomething > > > { > > > var i:int; > > > for(i=0;i++;i<10) > > > { > > > } > > > } > > > > > > Is functionally identical to this: > > > > > > function doSomething > > > { > > > for(var i:int =0;i++;i<10) > > > { > > > } > > > } > > > > Wrong. It's not. > > > > In the latter example, i is not available after the loop. In the first > > example, it is. > > > > var i:int; > > for (i = 0; i < 10; i++) > > { > > if (i == 5) break; > > } > > trace(i); > > -- 5 > > > > There are a multitude of uses for this, and I do it all the > > time. Additionally, I read somewhere many moons ago (back in my FLASM days) > > that declaring variables outside a for loop is less bytecode and uses less > > memory. I don't believe that applies to the counter declaration, but I do > > know it applies to the comparison as well as vars declared inside the for > > loop. However, this level of optimization is only useful in a practical way > > on mobile and some games. > > > > _______________________________________________ > > Flashcoders mailing list > > [email protected] > > http://chattyfig.figleaf.com/mailman/listinfo/flashcoders > > > _______________________________________________ > Flashcoders mailing list > [email protected] > http://chattyfig.figleaf.com/mailman/listinfo/flashcoders > _______________________________________________ Flashcoders mailing list [email protected] http://chattyfig.figleaf.com/mailman/listinfo/flashcoders _______________________________________________ Flashcoders mailing list [email protected] http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
